Leon Festinger and his colleagues conducted a well-known disguised participant observation study by infiltrating the Seekers, a doomsday cult predicting the world's end on December 21, 1954. By hiding their identities as researchers, they were able to meticulously document the members' psychological coping mechanisms when the prophecy failed. They noted that the members, rather than abandoning their beliefs, concluded that their own faith had prevented the apocalypse—a finding that Festinger later used to develop the theory of cognitive dissonance.